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Lessons > Feedback Effects > Step 2

There are several important natural systems that may be affected by greenhouse warming as atmospheric CO₂ rises. Some of these systems may release even more CO₂ into the atmosphere, speed up the warming, and cause a positive feedback loop. Which feedback effects will actually take place is hard to predict in such a complex system, but a model for one feedback effect is included in the simulator: melting tundra. If the arctic tundra were to melt as temperatures rise, its stored carbon would enter the system. You will find two possible scenarios. One model assumes that 1/12 of the tundra will melt over 100 years. The other predicts that 1/6 will melt over that same time period.

Assume that, in this hypothetical scenario, the tundra melting is inevitable and there is a 2% increase in fossil fuel consumption. Which of the two rates of melting would:

1. Have an impact on coastal seaweed populations in 2060? How great an impact?
2. Have an impact on atmospheric carbon in 2110 that is similar to another scenario you’ve investigated? What commonalities exist between these two scenarios?